Re: ifTable Extensions

[Keith McCloghrie <[e-mail]>]

On the contrary, Sandra's response was entirely accurate, and I think
the explanation and example in RFC 1904 (pages 9-11) is quite sufficient.

Keith.

> The response from Sandra, was mostly correct, but she missed an important
> distinction about compliances. That is, strictly speaking, an agent implementation
> either meets (or does not meet) a requirements specification. A MODULE-COMPLIANCE
> is a requirements specification. There is no such thing as being
> "conformant to a MIB module". An implementation can only be compared to
> a requirements specification. All this conformance and compliance terminology
> is explained in the book "Understanding SNMP MIBs" by perkins and mcginnis,
> with ISBN 0-13-437708-7. See pages 130-136 for a discussion and examples
> of the MODULE-COMPLIANCE construct.
> 
> The OBJECT-GROUP and NOTIFICATION-GROUP constructs are used to group together
> related objects and events. Instances of these are specified in a 
> MODULE-COMPLIANCE to indicate requirements and are specified in a
> AGENT-CAPABILITIES to show implementation. In Understanding SNMP MIBs,
> the groups are described on pages 127-130, and the agent capabilities
> is described on pages 136-141. Two extensive examples of their usage
> are shown on pages 233-240, 364-366, and 382-384.
> 
> On Fri, 4 Apr 1997 10:52:27 -0800 (PST)  Sandra Durham wrote:
> >> 
> >> Can anyone shed some light on the use of the ifGeneralGroup and ifPacketGroup
> >> They seem to be just repackaged ifTable objects.  They are not defined as 
> >> tables so it does not look like they can be retrieved from an agent.
> >
> >ifGeneralGroup, and ifPacketGroup are part of the conformance statements
> >for the IF-MIB.  If you are unfamiliar with conformance issues,
> >you should probably go read rfc1904.
> >
> >the basic deal here is that an agent implementation can be considered
> >conformant to the IF-MIB if it implements the appropriate
> >groups for a given interface media type.  And thus the ifTable will
> >have sparse rows. (as in if media type A requires only the
> >ifGeneralGroup, then the associated ifTable rows will return
> >noSuchInstance for things like ifInUcastPkts, etc).
> >
> >Sandra Durham
> 
> 
> Regards,
> /[e-mail], David T. Perkins
> Date: 04/04/97, Time: 14:46:33
> 
> 
>